fix: cython 3.2 compatibility

Author: oscarbenjamin

bin/coverage.sh

@@ -18,7 +18,7 @@ pip uninstall -y cython
 pip install --pre cython       # unpinned to pick up new releases in CI
 # pip install cython==3.1.0a1  # known working version for Python < 3.13
 
-meson setup build -Dcoverage=true
+meson setup build -Dcoverage=true -Dflint_version_check=false
 spin run -- coverage run $RC -m flint.test $@
 coverage report $RC -m --sort=cover
 coverage html $RC

src/flint/types/_gr.pyx

@@ -602,7 +602,7 @@ cdef class gr_ctx(flint_ctx):
     ###
     # Square Roots
 
-    def is_square(self, x) -> bool | None:
+    def is_square(self, x):
         """
         Returns whether x is a perfect square in the context.
         """